Development of Fatigue Crack Propagation Technique for Freestanding Nano-Films

Stochastic modeling of fatigue crack propagation

This paper presents a stochastic model of fatigue-induced crack propagation in metallic materials. The crack growth rate predicted by the model is guaranteed to be non-negative. The model structure is built upon the underlying principle of Karhunen±Lo eve expansion and does not require solutions of stochastic di€erential equations in either Wiener integral or Itô integral setting. As such this ...

Crack propagation in a Tantalum nano-slab

Using molecular dynamics with an accurate many-body potential for metallic Tantalum, we studied crack propagation in a pre-notched nano-slab under uniaxial strain in a [100] direction. We study dislocation emission from the crack tip for various strain rate and temperatures, focusing on the influence of the local temperature at the crack tip on the propagation of the crack. We find a close conn...

Fatigue crack propagation in microcapsule - toughened epoxy

The addition of liquid-filled urea-formaldehyde (UF) microcapsules to an epoxy matrix leads to significant reduction in fatigue crack growth rate and corresponding increase in fatigue life. Mode-I fatigue crack propagation is measured using a tapered doublecantilever beam (TDCB) specimen for a range of microcapsule concentrations and sizes: 0, 5, 10, and 20% by weight and 50, 180, and 460 lm di...

High Temperature Fatigue Crack Propagation in INCONEL718

Ultra Low Cycle Fatigue of Axisymmetric Freestanding Nanoscale Gold Films

We present ultra low-cycle fatigue experiments of axisymmetric nano-crystalline gold films of nano-thickness deformed by a spherical indenter using a recently developed freestanding membrane test. Freestanding membranes of gold were centrally deflected using a spherical indenter attached to a MEMS load cell. Fabrication of the films for these experiments yielded films 100 nm thick and 500 μm in...